This grant will provide continued NIH support to maintain the Caribbean Primate Research Center (CPRC). The CPRC consists of four integrated facilities: (1) Cayo Santiago, a unique free-ranging island colony of Indian-origin rhesus monkeys (Macaca mulatta);(2) the Sabana Seca Field Station, the CPRC's headquarters located 10 miles outside of San Juan, that houses rhesus monkeys derived from the Cayo Santiago colony in various outdoor configurations for biomedical and behavioral studies that are not feasible on free-ranging animals;(3) the Laboratory of Virology and Genetics (LVG), located on the Medical Sciences Campus (MSC), in San Juan;and (4) the Laboratory of Primate Morphology and Genetics (LPMG), which is also located on the MSC, and houses the CPRC Skeletal Collections, unique assemblages of nonhuman primate skeletons for genetic, developmental, pathological and anatomical research. As described in this proposal, CPRC is organized into four complementary and integrated divisions: Primate Resources, Virology and Genetics, Behavior and Neurosciences, and Primate Morphology &Genetics. Funds are requested in this application only to maintain CPRC basic infrastructure of Primate Resources, which are used to support numerous research projects across the United States. This core grant will also allow CPRC to seek additional support to launch collaborative research projects with mainland and international investigators. With continued NIH support, the CPRC will remain a significant national research resource and will be able to provide healthy Indian-origin rhesus monkeys of defined genetic and virological background to NIH-sponsored research programs.